Self polymerizable phenylquinoxalines, their preparation and use in polyphenylquinoxaline homopolymers and copolymers

ABSTRACT

A polyphenylquinoxaline which consists of 1 to 100 mole percent of structural elements of the formula (IV) ##STR1## and of 0-99 mole percent of the following repeat unit of formula (V) ##STR2## where R is selected from the group consisting of H, an alkyl group, a carbocyclic aromatic group, a heterocyclic aromatic group, or an alkoxy group, Ar 1  is a carbocyclic aromatic or heterocyclic aromatic group, and B is selected from the representative group consisting of: 
     
         Ar.sub.2 --Z--Ar.sub.3                                     (i) 
    
     where Ar 2  and Ar 3  are the same or different carbocyclic aromatic or heterocyclic aromatic group and Z is selected from the representative group consisting of CO, SO or SO 2  ; 
     
         Z&#39;--Ar.sub.4 --Z&#39;                                          (ii) 
    
     where Z&#39; is an activated carbocyclic aromatic or heterocyclic aromatic group and Ar 4  is an aliphatic group, a carbocyclic aromatic or heterocyclic aromatic group. A process for manufacture a self polymerizable phenylquinoxaline subject to polymerization by aromatic nucleophilic substitution. The use of these polyphenylquinoxalines and there copolymers as thermally stable thermal plastics for use in aerospace, high temperature adhesive, microelectronic and membrane (gas and molecular separation membrane) application.

This is a continuation of copending application Ser. No. 368,572, filedon Jun. 20, 1989, now U.S. Pat. No. 5,030,704.

TECHNICAL FIELD

This invention describes the manufacture of self polymerizablephenylquinoxalines and their use in the preparation ofpolyphenylquinoxalines and copolymers containing of self polymerizablephenylquinoxalines monomer.

The present invention relates to new polyquinoxaline homopolymers andcopolymers, their use as thermoplastic in aerospace, microelectronicsand membrane application such as gas separation membranes and molecularseparation membranes and a process for manufacturing 2,3-diarylsubstituted-6-fluoro-quinoxalines where at least one of the aryl groupsis hydroxylated.

Polyquinoxalines, herein sometimes referred to as PPQ's, are a wellestablished class of high performance thermoplastics with provenpotential in aerospace, microelectronics and membrane applications.

BACKGROUND ART

PPQ's are normally prepared by the reacting of bis-alpha-carbonylcompounds with an organic tetramine. In U.S. Pat. Nos. 3,852,244 and3,956,238, Heath et al., has disclosed the formation of polyetherquinoxalines from a wide variety of polyether bis-alpha-carbonylcompounds and aromatic organic tetramines.

In "Synthesis of poly(phenylyquinoxaline) with High Glass TransitionTemperatures," Polymer Prep, 28, 71 (1987), Harris et al. has describedthe synthesis of various bis(phenylglyoxalyl) napthalenes and their usein the preparation of PPQ's.

In "The Synthesis and Characterization of Phenolic Hydroxyl TerminatedPolyphenylquinoxaline Oligomers," Polymer Prep, 28, 69 (1987), Labadieet al. has described the preparation of hydroxy terminated polyphenylquinoxalines.

In U.S. Pat. No. 3,326,915, Jackson et al. described the preparation anduse of various self-polymerizable benzopyrazin or quinoxalines, butthese self-polmerizable monomers are polymerized by the same classicalprocedures as described in Heath et al. above.

More recently, Connell et al. described in "Synthesis ofPolyphenylquinoxalines via Aromatic Nucleophilic Displacement," PolymerPrep, 29, 172 (1988), the formation of PPQ's by reactingbis-hydroxyphenyl-quinoxalines with an activated difluoro monomers underaromatic nucleophilic substitution reaction conditions.

Hedrick et al. have also described in "Synthesis of Poly(arylether-phenylquinoxaline)" Proceedings from Polymeric Material Science &Engineering, 59, 42 (1988), the formation of PPQ's by reactingbis-fluoro-polyphenylated-quinoxalines with various bis-hydroxylatedaromatic compounds under aromatic nucleophilic substitution reactionconditions.

However, the aromatic nucleophilic substitution process for making PPQ'sstill requires the purification and use of two independent components.

Thus, it appears desirable to manufacture a self polymerizationquinoxaline which polymerizes under aromatic nucleophilic substitutereaction conditions to yield PPQ's and copolymers containing PPQ'sincorporating the self polymerizable phenylquinoxalines. These PPQ andPPQ copolymers especially PPQ copolymers containingpolyether-ether-ketone, sometimes referred herein as PEEK, repeat unitsor PPQ copolymers containing polyethersulfone, sometimes herein referredto as PES, repeat units have excellent thermal and mechanical propertiesand are ideally suited as useful thermoplastic in the areas ofaerospace, high temperature adhesive, microelectronic and membraneapplications. These copolymers have properties that are tunable to makehigh temperature thermoplastics, highly crystalline thermoplastics,lowly crystalline thermoplastics, organic soluble thermoplastics ororganic insoluble thermoplastics.

DISCLOSURE OF THE INVENTION

It is an object of this invention to provide novel, self polymerizable,phenylquinoxalines incorporating within the same chemical structure anaromatic nucleophilic displacable group and a group which can displacethe displacable group.

It is a further object of this invention to provide novel PPQ's preparedby polymerizing the self polymerizable phenylquinoxalines.

A further object of this invention is to provide novel PPQ copolymersbased on the self polymerizable phenylquinoxalines and at least oneother systems which can undergo aromatic nucleophilic substitutionpolymerization.

A further object of this invention is to provide a usable process forthe manufacturing of 2,3-diaryl-6-fluoro-quinoxalines where at least onearyl group is hydroxylated.

The novel self polymerizable quinoxalines have the following formula(I): ##STR3## where Y is selected from the group consisting of F, Cl orNO₂ and Y is in either the 6 or 7 position of the quinoxaline ringsystem and where R is selected from the group consisting of H, an alkylgroup having usually 1 to 16 carbon atoms, a carbocyclic aromatic group,a heterocyclic aromatic group, or an alkoxy group having usually 1 to 8carbon atoms.

The phenylquinoxalines of formula (I) can be manufactured according tothe following reaction scheme: ##STR4## where Y and R are as previouslydefined. Thus, a representative compound of formula (II),4-fluoro-1,2-diaminobenzene, is reacted with a representative compoundof formula (III), 4-hydroxybenzil, in the presence of a chlorinatedhydrocarbon solvent such as chloroform in the presence of an strongorganic acid catalyst such as trifluoroacetic acid, para-toluenesulfonicacid, or trichloroacetic acid.

The phenylquinoxalines of this invention can be used as monomers for themanufacture of PPQ's and as monomers for manufacturing copolymerscontaining PPQ's and other monomer systems which undergo aromaticnucleophilic substitution polymerization which consist of 1-100 molepercent and preferrably from about 10 to 100 mole percent of repeat unitof formula (IV) ##STR5## and 0-99 mole percent and preferrably fromabout 90 to 0 mole percent of repeat unit formula (V) ##STR6## where Ris as previously defined, Ar₁ is a carbocyclic aromatic or heterocyclicaromatic group, and B is selected from the representative groupconsisting of:

    Ar.sub.2 --Z--Ar.sub.3                                     (i)

where Ar₂ and Ar₃ are the same or different a carbocyclic aromatic orheterocyclic aromatic group and Z is selected from the representativegroup consisting of CO, SO or SO₂

    Z'--Ar.sub.4 --Z'                                          (ii)

where Z' is an activated carbocyclic aromatic or heterocyclic aromaticgroup and Ar₄ is an aliphatic group having usually 1 and 16 carbonatoms, a carbocyclic aromatic or heterocyclic aromatic group.

Repeat units of formula (V) can be made by the following reactionscheme: ##STR7## where Y, Ar₁ and B are as previously defined. Thus, andihydroxyaryl compound of formula (VI) such as hydroquinone(1,4-dihydroxybenzene), resorcinol (1,3-dihydroxybenzene), or variousdihydroxynaphthylenes is reacted with a disubstituted B linked arylcompound such as 4,4'-difluorobenzophenone,4,4'-difluorodiphenylsulfone, 4,4'-difluorodiphenylsulfoxide,4,4'-dinitrobenzophenone, 4,4'-dinitrodiphenylsulfone, or4,4'-dichlorobenzophenone.

The polymerization reaction is carried out under standard aromaticnucleophilic reaction conditions which involve mixing the monomerstogether in an appropriate organic solvent with excess of K₂ CO₃ asproton absorption component and removing the water as it is formed inthe case of the above described copolymers.

BEST MODE FOR CARRYING OUT THIS INVENTION

Applicants have found that the PPQ's derived from phenylquinoxalines offormula (I) or copolymers having at least 1 mole percent of repeat unitsderived from self polymerizable phenylquinoxaline of formula (I)represent a new and novel class of thermoplastic PPQ's. The PPQ's andcopolymers of this invention are formed using a nuclephilic substitutionaction from a self polymerizable phenylquinoxaline which has an activeleaving group such as fluorine, chlorine or nitro, displacable by anucleophilic site on the same molecule usually an aromatic hydroxy groupwhere the quinoxaline ring system serves as an activating group. Thesepolymers are important because of their excellent thermo-mechanicalproperties and the mild conditions under which they are formed.

In preparing the homo PPQ's, a solution of the self polymerizingphenylquinoxaline of formula (I) is dissolved in a mixture ofN-methylpyrollodone (NMP) and toluene to afford monomer solubilitycontaining an excess of K₂ CO₃ which absorbs the protonic acid generatedduring aromatic nucleophilic substitution under nitrogen. The polymer isformed as a fibrious component which can be dissolved in chlorinatedhydrocarbons and reprecipitated from methanol. Although the selfpolymerizable phenylquinoxalines of formula (I) can have the leavinggroup Y substituted in the sixth or seventh position of thephenylquinoxaline ring system, the pure components, that is those thathave either all six substituted leaving groups or seven substitutedleaving groups, can be used as the self polymerizing monomer.

The use of these pure components results in homo PPQ's which havegreater order and a rigidity and as well PPQ copolymers with these sameenhanced properties. Copolymers using self polymerizablephenylquinoxalines of formula (I) in a mole percent greater than orequal to 1, involve reacting the phenylquinoxaline of formula (I) withpreferrably a near 1:1 mixture of an activated disubstituted aromaticcomponent where the substituents are nucleophilic substitution leavinggroups such as fluorine, chlorine or nitro and an aromatic diol wherethe diols are directly attached to an aromatic ring such as1,4-di-hydroxy benzene. Small excess of either the aromatic diols or thedisubstituted aromatic compounds are acceptable with the excess usuallyranging from about 1 to 10% by weight.

These copolymers are useful in applications where the phenylquinoxalinestructure increases the polymers thermal stability and imparts adifferent morphology to the polymer which can improve the polymersrigidity and packing efficiency resulting in improved fiber formingproperties and more durable film or reinforcing agents for molecularcomposities.

Copolymers consisting of 51-100 mole percent of repeat units of formula(IV) and 49-0 mole percent of repeat units of formula (V) areparticularly preferred for applications where the thermoplasticcharacter of the PPQ block predominate the characteristic of thecopolymer. This application include most of the standard applicationsthat PPQ's are traditionally used for in industry. However, theincorporation of up to 49 mole percent of repeat units of formula (V)will allow modifications of the PPQ normal physical properties toaccomplish polymers tailors made for a given application.

Copolymer consisting of 1-50 mole percent of repeat units of formula(IV) and 99-50 mole percent of repeat units of formula (V) represent theother side of the spectrum of copolymers, that is copolymers where theblock incorporating repeat units of formula (V) predominate. Thesecopolymers will express more of the native homopolymer characteristicsof homopolymer consisting of 100 mole percent of repeat units of formula(V). However, the inclusion of at least 1 mole percent of repeat unitsof formula (IV) will allow wide latitude in the design of particularpolymers for a given application.

The copolymers which incorporate PEEK blocks show a variation incopolymer properties as the amount of PEEK [poly(ether-ether ketones]content is increased. In the 25 to 50 mole present of PEEK blockincorporated in the copolymer a shift in the copolymers final propertiesin that the T_(g) increases from a T_(g) platuea that dominates thecopolymers from 50 to 90 percent PEEK composition.

In the case of PPQ-PEEK copolymers, the compounds of formula (VI) whichare particularly preferred are selected from the illustrative andrepresentative group consisting of hydroquinone (1,4-dihydroxybenzene),resorcinol (1,3-dihydroxybenzene), or various dihydroxynaphthylenes;while the particularly preferred compounds of formula (V) are selectedfrom the illustrative and representative group consisting of4,4'-difluorobenzophenone, 4,4'-dinitrobenzophenone, or4,4'-dichlorobenzophenone.

The incorporation of PES (polyethersulfone) on the other hand onlycauses a steady increase in the T_(g) of the copolymers as the molepercent is increased from 25 to 75%.

In the case of PPQ-PES copolymers, the compounds of formula (VI) whichare particularly preferred are selected from the illustrative andrepresentative group consisting of hydroquinone (1,4-dihydroxybenzene),resorcinol (1,3-dihydroxybenzene), or various dihydroxynaphthylenes;while the particularly preferred compounds of formula (V) are selectedfrom the illustrative and representative group consisting of4,4'-difluorodiphenylsulfone, 4,4'-dinitrodiphenylsulfone or4,4'-dichlorodiphenylsulfone.

Other dihydroxy compound of formula (IV) include4,5-bis(4-hydroxyphenyl)-2-phenylimidazole. Other difluoro compounds offormula (V) are selected from the illustrative and representative groupconsisting of 1,3-bis(4-fluorobenzoyl)benzene,1,4-bis(4-fluorobenzoyl)benzene, 4,4'-bis(4-fluorobenzoyl)diphenylether,4,4'-bis(4-fluorobenzoyl)diphenylmethane, 4,4'-bis(4-fluorobenzoyl)diphenylsulfone,2,6-bis(4-fluorobenzoyl)naphthalene or4,4'-bis(4-fluorobenzoyl)biphenyl.

The invention will be better understood by reference to the followingexamples which are included for the purpose of illustration and notlimitation.

EXAMPLE 1 Preparation of Self-Polymerizable Phenylouinoxalines

This example illustrates the preparation of a near 50-50 mixture of2-phenyl-3-(4-hydroxyphenyl)-6-fluoroquinoxaline and2-(4-hydroxyphenyl)-3-phenyl-6-fluoroquinoxaline.

To a one litre round-bottomed flask equipped with an overhead stirrerand a reflux condensor was added 73.12 grams (0.323 moles) of4-hydroxybenzil, 40.77 grams (0.323 moles) of4-fluoro-1,2-diaminobenzene and 500 mls of chloroform. After 5 drops oftrifluoroacetic acid was added, the solution was stirred and heated atreflux for 5 hrs. The solution was allowed to cool to room temperature,extra mls of water, and dried over MgSO₄. After the solvent was removedunder reduced pressure, the residue was recrystallized 3 times from 95%ethanol to yield 2.97 grams (91%) of a bright yellow powder formula(Ia): ##STR8## Compound (Ia) had the following physical properties:mp=82°-117° C.; IR (KBr) 1600 cm₋₁ quinoxaline absorption, 3123 cm₋₁ OHabsorption; ¹ H-NMR (CDCl₃) 6.6 ppm (s, 1H, OH) and 7.3-8.3 ppm (m, 12H,aromatic). Anal. Calcd. C₂₀ H₁₃ FN₂ O: C, 75.94; H 4.14. Actual: C,76.04; H, 4.20.

EXAMPLE 2 Homopolymerization

This example illustrates the preparation of a PPQ homopolymer based onthe self polymerizable phenylquinoxaline of formula (Ia) prepared inExample 1.

25 grams (0.079 moles) of monomer (Ia) from example 1 was dissolved in200 mls of a 50:50 (v/v) solutions of NMP/toluene containing excess K₂O₃ under nitrogen. The mixture was stirred for 4 hrs at 160° C. duringwhich time the water of condensation was collected in a Dean Stark trap.The toluene was then removed as the mixture was heated to 190° C. for 1hr. The temperature was then raised to 202° C. for an additional hr. Thedark red mixture was diluted with 200 mls NMP and added to 2000 mls of astirred 75:25 (v/v) solution of methanol/acetic acid. The fibrous whitePPQ was collected by filtration, dissolved in chloroform and filtered.The polymer was reprecipitated into methanol and in refluxing water; andthen dried at 150° C. under reduced pressure for 18 hrs.

The homopolymer was obtained as a white fibrous material which displayedthe following properties: [n]=1.23 dl/g, T_(g) =247° C., and TGA (5%weight loss) 555° D. (N₂) and 565° C. (air), and was soluble in NMP,DMAc, m-cresol, and chlorinated hydrocarbons.

A thin film (3 mil) of the homopolymer was cast from NMP and subjectedto preliminary stress-strain measurements according to ASTM D882. Thetensile strength of the film was 107±6 MPA (15,515 PSI) and its tensilemodulus was 3.18±0.15 Gpa (461,100 PSI).

A sample of the homopolymer was compression molded at 300° C. and 1000PSI. Preliminary measurements on the molded specimen gave a flexuralmodulus of 2.8±0.3 MPa and G_(1C) =0.68±0.11 N-m/m².

EXAMPLE 3

This example illustrates the preparation of a PPQ homopolymer based oneither a pure 2-phenyl-3-(4-hydroxyphenyl)-6-fluoro-quinoxaline or pure2-(4-hydroxyphenyl)-3-phenyl-6-fluoro-quinoxaline.

25 grams (0.079 moles) of 2-(4-hydroxyphenyl)-3-phenyl-6-fluoroquinoxaline from example 1 is dissolved in 200mls of a 50:50 (v/v) solutions of NMP/toluene containing excess K₂ O₃under nitrogen. The mixture is stirred for 4 hrs at 160° C. during whichtime the water of condensation is collected in a Dean Stark trap. Thetoluene is then removed as the mixture is heated to 190° C. for 1 hr.The temperature is then raised to 202° C. for an additional hr. The darkred mixture is diluted with 200 mls NMP and added to 2000 mls of astirred 75:25 (v/v) solution of methanol/acetic acid. The fibrous whitePPQ is collected by filtration, dissolved in chloroform and filtered.The polymer is reprecipitated into methanol and in refluxing water; andthen dried at 150° C. under reduced pressure for 18 hrs.

Preparation of PPO-PEEK Co-Polymers EXAMPLE 4

This example illustrates the preparation of a PPQ-PEEK copolymerconsisting of 75 mole percent of a PPQ repeat unit of formula (II) basedon the self polymerizable phenylquinoxalines of formula (Ia), preparedin Example 1, and 25 mole percent of a PEEK repeat unit of formula (III)based on the reaction of hydroquinone and 4,4'-difluorobenzophenone.

18.75 grams (0.0593 moles) of self polymerizable phenylquinoxaline (Ia)from example 1, 1.087 grams (0.0099 moles) of hydroquinone, and 2.155grams (0.0099 moles) of 4,4'-difluorobenzophenone were dissolved in 200mls of a 50:50 (v/v) solutions of NMP/toluene containing excess K₂ CO₃under nitrogen. The mixture was stirred for 4 hrs at 160° C. duringwhich time the water of condensation was collected in a Dean Stark trap.The toluene was then removed as the mixture was heated to 190° C. for 1hr. The temperature was then raised to 202° C. for an additional hr. Thedark red mixture was diluted with 200 mls NMP and added to 2000 mls of astirred 75:25 (v/v) solution of methanol/acetic acid. The fibrous whitePPQ-PEEK copolymer was collected by filtration, dissolved in chloroformand filtered. The polymer was reprecipitated into methanol and inrefluxing water; and then dried at 150° C. under reduced pressure for 18hrs.

The homopolymer was obtained as a white fibrous material which displayedthe following properties: [n]=0.81 dl/g in m-cresol at 30.1° C., andT_(g) =222° C.

EXAMPLE 5

This example illustrates the preparation of a PPQ-PEEK copolymerconsisting of 50 mole percent of a PPQ repeat units of formula (II)based on the self polymerizable phenylquinoxalines of formula (Ia),prepared in Example 1, and 50 mole percent of a PEEK repeat unit offormula (III) based on the reaction between hydroquinone and4,4'-difluorobenzophenone.

12.5 grams (0.0395 moles) of self polymerizable phenylquinoxaline (Ia)from example 1, 2.175 grams (0.0198 moles) of hydroquinone, and 4.309grams (0.0198 moles) of 4,4'-difluorobenzophenone were dissolved in 200mls of a 50:50 (v/v) solutions of NMP/toluene containing excess K₂ CO₃under nitrogen. The mixture was stirred for 4 hrs at 160° C. duringwhich time the water of condensation was collected in a Dean Stark trap.The toluene was then removed as the mixture was heated to 190° C. for 1hr. The temperature was then raised to 202° C. for an additional hr. Thedark red mixture was diluted with 200 mls NMP and added to 2000 mls of astirred 75:25 (v/v) solution of methanol/acetic acid. The fibrous whitePPQ-PEEK copolymer was collected by filtration, dissolved in chloroformand filtered. The polymer was reprecipitated into methanol and inrefluxing water; and then dried at 150° C. under reduced pressure for 18hrs.

The homopolymer was obtained as a white fibrous material which displayedthe following properties: [n]=1.19 dl/g in m-cresol at 30.1° C. andT_(g) =170° C.

EXAMPLE 6

This example illustrates the preparation of a PPQ-PEEK copolymerconsisting of 25 mole percent of a PPQ repeat units of formula (II)based on the self polymerizable phenylquinoxalines of formula (Ia),prepared in Example 1, and 75 mole percent of a PEEK repeat unit offormula (III) based on the reaction between hydroquinone and4,4'-difluorobenzophenone.

6.25 grams (0.0198 moles) of self polymerizable phenylquinoxaline (Ia)from example 1, 3.262 grams (0.0296 moles) of hydroquinone, and 6.464grams (0.0296 moles) of 4,4'-difluorobenzophenone were dissolved in 200mls of a 50:50 (v/v) solutions of NMP/toluene containing excess K₂ CO₃under nitrogen. The mixture was stirred for 4 hrs at 160° C. duringwhich time the water of condensation was collected in a Dean Stark trap.The toluene was then removed as the mixture was heated to 190° C. for 1hr. The temperature was then raised to 202° C. for an additional hr. Thedark red mixture was diluted with 200 mls NMP and added to 2000 mls of astirred 75:25 (v/v) solution of methanol/acetic acid. The fibrous whitePPQ-PEEK copolymer was collected by filtration, dissolved in chloroformand filtered. The polymer was reprecipitated into methanol and inrefluxing water; and then dried at 150° C. under reduced pressure for 18hrs.

The homopolymer was obtained as a white fibrous material which displayedthe following properties: [n]=1.08 dl/g in conc. H₂ SO₄ at 30.1° C. andT_(g) =170° C.

EXAMPLE 7

This example illustrates the preparation of a PPQ-PEEK copolymerconsisting of 10 mole percent of a PPQ repeat units of formula (II)based on the self polymerizable phenylquinoxalines of formula (Ia),prepared in Example 1, and 90 mole percent of a PEEK repeat unit offormula (III) based on the reaction between hydroquinone and4,4'-difluorobenzophenone.

2.5 grams (0.0079 moles) of self polymerizable phenylquinoxaline (Ia)from example 1, 3.914 grams (0.0356 moles) of hydroquinone, and 7.757grams (0.0356 moles) of 4,4'-difluorobenzophenone were dissolved in 200mls of a 50:50 (v/v) solutions of NMP/toluene containing excess K₂ CO₃under nitrogen. The mixture was stirred for 4 hrs at 160° C. duringwhich time the water of condensation was collected in a Dean Stark trap.The toluene was then removed as the mixture was heated to 190° C. for 1hr. The temperature was then raised to 202° C. for an additional hr. Thedark red mixture was diluted with 200 mls NMP and added to 2000 mls of astirred 75:25 (v/v) solution of methanol/acetic acid. The fibrous whitePPQ-PEEK copolymer was collected by filtration, dissolved in chloroformand filtered. The polymer was reprecipitated into methanol and inrefluxing water; and then dried at 150° C. under reduced pressure for 18hrs.

The homopolymer was obtained as a white fibrous material which displayedthe following properties: [n]=0.37 dl/g in conc. H₂ SO₄ at 30.1° C.,T_(g) =165° C., and T_(m) =320° C.

Preparation of PPO-PES Co-Polymers EXAMPLE 8

This example illustrates the preparation of a PPQ-PES copolymerconsisting of 75 mole percent of a PPQ repeat unit of formula (II) basedon the self polymerizable phenylquinoxalines of formula (Ia), preparedin Example 1, and 25 mole percent of a PES repeat unit of formula (III)based on the reaction of hydroquinone and 4,4'-difluorodiphenylsulfone.

18.75 grams (0.0593 moles) of self polymerizable phenylquinoxaline (Ia)from example 1, 1.087 grams (0.0099 moles) of hydroquinone, and 2.511grams (0.0099 moles) of 4,4'-difluorodephenylsulfone were dissolved in200 mls of a 50:50 (v/v) solutions of NMP/toluene containing excess K₂CO₃ under nitrogen. The mixture was stirred for 4 hrs at 160° C. duringwhich time the water of condensation was collected in a Dean Stark trap.The toluene was then removed as the mixture was heated to 190° C. for 1hr. The temperature was then raised to 202° C. for an additional hr. Thedark red mixture was diluted with 200 mls NMP and added to 2000 mls of astirred 75:25 (v/v) solution of methanol/acetic acid. The fibrous whitePPQ-PES copolymer was collected by filtration, dissolved in chloroformand filtered. The polymer was reprecipitated into methanol and inrefluxing water; and then dried at 1 50° C. under reduced pressure for18 hrs.

The homopolymer was obtained as a white fibrous material which displayedthe following properties: [n]=1.06 dl/g in m-cresol at 30.1° C. andT_(g) =240° C.

EXAMPLE 9

This example illustrates the preparation of a PPQ-PES copolymerconsisting of 50 mole percent of a PPQ repeat units of formula (II)based on the self polymerizable phenylquinoxalines of formula (Ia),prepared in Example 1, and 50 mole percent of a PES repeat unit offormula (III) based on the reaction between hydroquinone and4,4'-difluorodiphenylsulfone.

12.5 grams (0.0395 moles) of self polymerizable phenylquinoxaline (Ia)from example 1, 2.175 grams (0.0198 moles) of hydroquinone, and 5.022grams (0.0198 moles) of 4,4'-difluorodiphenylsulfone were dissolved in200 mls of a 50:50 (v/v) solutions of NMP/toluene containing excess K₂CO₃ under nitrogen. The mixture was stirred for 4 hrs at 160° C. duringwhich time the water of condensation was collected in a Dean Stark trap.The toluene was then removed as the mixture was heated to 190° C. for 1hr. The temperature was then raised to 202° C. for an additional hr. Thedark red mixture was diluted with 200 mls NMP and added to 2000 mls of astirred 75:25 (v/v) solution of methanol/acetic acid. The fibrous whitePPQ-PES copolymer was collected by filtration, dissolved in chloroformand filtered. The polymer was reprecipitated into methanol and inrefluxing water; and then dried at 150° C. under reduced pressure for 18hrs.

The homopolymer was obtained as a white fibrous material which displayedthe following properties: [n]=1.16 dl/g in m-cresol at 30° C. and T_(g)=232° C.

EXAMPLE 10

This example illustrates the preparation of a PPQ-PES copolymerconsisting of 25 mole percent of a PPQ repeat units of formula (II)based on the self polymerizable phenylquinoxalines of formula (Ia),prepared in Example 1, and 75 mole percent of a PES repeat unit offormula (III) based on the reaction between hydroquinone and4,4'-difluorodiphenylsulfone.

6.25 grams (0.0198 moles) of self polymerizable phenylquinoxaline (Ia)from example 1, 3.262 grams (0.0296 moles) of hydroquinone, and 7.532grams (0.0296 moles) of 4,4'-difluorodiphenylsulfone were dissolved in200 mls of a 50 50 (v/v) solutions of NMP/toluene containing excess K₂CO₃ under nitrogen. The mixture was stirred for 4 hrs at 160° C. duringwhich time the water of condensation was collected in a Dean Stark trap.The toluene was then removed as the mixture was heated to 190° C. for 1hr. The temperature was then raised to 202° C. for an additional hr. Thedark red mixture was diluted with 200 mls NMP and added to 2000 mls of astirred 75:25 (v/v) solution of methanol/acetic acid. The fibrous whitePPQ-PES copolymer was collected by filtration, dissolved in chloroformand filtered. The polymer was reprecipitated into methanol and inrefluxing water; and then dried at 150° C. under reduced pressure for 18hrs.

The homopolymer was obtained as a white fibrous material which displayedthe following properties: [n]=1.08 dl/g in H₂ SO₄ at 30° C. and T_(g)=219° C.

All of the PEEK and PES copolymers of examples 4-10 had decompositiontemperatures (temperature until a 5% weight loss occurs in the TGAspectra) between 500° and 565° C. in nitrogen and between 505° and 550°C. in air.

What is claimed is:
 1. A self polymerizable phenylquinoxaline comprisinga compound of formula (I): ##STR9## where Y is selected from the groupconsisting of F, Cl and NO₂ and Y is in either the 6 or 7 position ofthe quinoxaline ring system and where R is selected from the groupconsisting of H, an alkyl group having from 1 to about 16 carbon atoms,a carbocyclic aromatic group, a heterocyclic aromatic group, or analkoxy group having from 1 to 8 carbon atoms.
 2. A self polymerizablephenylquinoxaline according to claim 1 where Y is F.
 3. A selfpolymerizable phenylquinoxaline according to claim 1 where Y is Cl.
 4. Aself polymerizable phenylquinoxaline according to claim 1 where Y isNO₂.
 5. A self polymerizable phenylquinoxaline according to claim 1where R is H.
 6. A self polymerizable phenylquinoxaline according toclaim 2 where R is H.
 7. A self polymerizable phenylquinoxalineaccording to claim 3 where R is H.
 8. A self polymerizablephenylquinoxaline according to claim 4 where R is H.